Optimation Formula Yoghurt of Goat Milk and Mushroom with Mixture Design and Potential Functional Properties

Abstract

Etawah Breed goat milk has not been widely consumed in Indonesia because it has distinctive characteristic of prengus smell so that it is not appreciated by the public, and the lack of public knowledge concerning the benefits of goat’s milk. Milk fermentation process causes the formation of distinctive flavor as the result of activities from lactic acid bacteria, such as acetaldehyde and diacetyl compounds that can reduce or even eliminate the prengus smell. Conventionally, the bacteria commonly used in the formulation of yoghurt were Lactobacillus bulgaricus and Streptococcus thermophilus. However, it was later discovered that the bacteria are not sufficient to maintain the health of digestive tract. To increase the functional value of the yoghurt product, probiotic bacteria should be added. Lactobacillus acidophilus is one of probiotic bacteria that can be added in the making of yoghurt. White oyster mushrooms and shiitake mushrooms are two types of mushrooms well known by the people of Indonesia with affordable prices and potential prebiotic. The fiber and polysaccharides content in these two mushrooms, makes the mushrooms as potential prebiotic. Probiotic yoghurt enriched with the addition of prebiotics produces the product known as synbiotic yoghurt. The formulation of yoghurt can be performed by adding full cream and skim milk. Mixture design is a collection of mathematical and statistical techniques that are useful on modeling and analysis of the problem of the response that is influenced by several variables. The method serves to determine the optimum formula. Indonesia has a huge wealth of biodiversity, including medicinal plants and spices. The spices that have been known for a long time in Indonesia are ginger, cloves, anise and cinnamon. The addition taste in the form of spices syrup into yoghurt, will create a new taste variations. This research aims to assess the formulation of goat milk yoghurt to get the optimum formula using mixture design and determining the functional characteristics of yoghurt optimum formula based on resistance to gastric pH, antimicrobial activity based on E. coli, and amino acid content. This research also aims to examine the effects of spices syrup addition on the preference of the yoghurt. The result showed that the optimum formula was a mixture of 0.5% white oyster mushroom, 3% skim milk, 96% goat skim milk. The optimum formula has pH of 4.30, viscosity of 6200 cP, total titrated acid 1.08%, lactic acid bacteria 1.1 x 1010 cfu/ml. For a functional food criteria of 9.5 x 105 cfu/ml the yoghurt resists based on gastrointestinal tract pH, has 10.9 mm antimicrobial activity based on E.coli and content amino acid. The result of hedonic test that the addition of spices syrup as a topping that the highest score of the taste properties were 4.37 for 4 ml addition of ginger syrup; 4.13 for 6 ml addition of mixture of cloves-cardamom-anise syrup, and 4.23 for 6 ml addition of mixture of cloves-cardamom-cinnamon syrup. Based on these results, the consumer preference was still at the level of netral.